Some of the advantages of a rotational grazing unit are the fringe benefits of higher stock density when compared to more extensive grazing situations. One of the obvious benefits is the more uniform distribution of excrement within paddocks provided management is in line to control distribution. The Controlled Rotation Grazing Unit on the Noble Research Institute's Pasture Demonstration Farm serves as a good example of uniform excrement distribution.
During the summer of 1997, we tested manure distribution in the paddocks to determine manure (and urine) distribution relative to our management, first within the paddocks and secondly under and near our one-wire electric fences. We tested two shapes of paddocks, one type was rectangular with a water lane at each end and the other was a triangular shape with water at the acute end. All paddocks had a gate at each corner to facilitate cattle moves at either end. A previously written article describes things we do to keep cattle on the paddocks and distributed as much as feasible (Ag News & Views, June Issue, 1994). Ask for a reprint if you wish.
Manure distribution under or near the electric fence was of interest because we feed on the ground under the wire. We knew that location was relatively free of manure, but how free? We sampled a band twelve feet wide, from directly under the fence out to six feet away on each side.
Anything within a two foot band (one foot on each side) of the electric fence was considered under the fence. Chart 1 shows the relative percentage of manure in each portion of the band on one side of the fence. One can see that the area under the fence contains a very small portion of manure within the six-foot band. In addition, only 0.7% of the linear under-the-fence location contained a manure deposit. Thus, that area is obviously a very clean area to feed on as compared to the of the paddock that is away from the fence. Wanna come to dinner?
Chart 2 and Chart 3 show the relative distribution of manure within the length and width of the paddocks. The paddocks were divided into one-quarter portions to present this data. The first portion (0-25%) was at the major cattle move gate in the rectangular paddocks and the acute end (water point) in the triangular paddocks.
Overall distribution is relatively good, but distributions had a considerable decline in each paddock shape at the far end from the water point and/or gate where most cattle moves were done. Our methods of keeping cattle on paddocks and managing for distribution in the paddock have been good, but not the best we can do. To try to get better distribution at the "far end" we need to do four major things: